Cylinder sleeve for internal combustion engines

Abstract

A cylinder sleeve for an internal combustion engine may include a bore-through cylindrical body having an inner sliding surface. The inner surface may have a surface finish with a rugosity defined by a valley-and-peak structure. The rugosity of the inner surface may have a ratio between a peak density and a mean radius of curvature of peaks that is higher than 150 and lower than 400. The rugosity may also have a ratio between the mean radius of curvature of peaks and an average height of peaks that is lower than 1500.

1 . A cylinder sleeve for an internal combustion engine, comprising:
 a bore-through cylindrical body having an inner sliding surface having a surface finish with a rugosity defined by a valley-and-peak structures;   wherein the rugosity of the inner surface has:
 a ratio between a peak density and a mean radius of curvature of peaks higher than 150 and lower than 400; and 
 a ratio between the mean radius of curvature of peaks and an average height of peaks lower than 1500. 
   
     
     
         2 . The cylinder sleeve according to  claim 1 , wherein the peak density is from 4,000 to 28,000 peaks per square millimeter. 
     
     
         3 . The cylinder sleeve according to  claim 1 , wherein the mean radius of curvature of peaks is from 86 to 105 peaks per millimeter. 
     
     
         4 . The cylinder sleeve according to  claim 1 , wherein the rugosity is formed via a magnetic surface finishing process carried out after a burnishing process. 
     
     
         5 . A magnetic surface finishing method for a cylinder sleeve of an internal combustion engine, comprising:
 arranging a magnetic pole inside the cylinder sleeve, close to an inner surface of the cylinder sleeve;   filling an inside of the cylinder sleeve with a magnetizable powder;   creating a magnetic field inside the cylinder sleeve; and   wearing down a plurality of peaks of the inner surface via friction with the magnetizable powder.   
     
     
         6 . The magnetic surface finishing method according to  claim 5 , wherein the magnetizable powder comprises has a granulometry from 4 to 300 micrometers. 
     
     
         7 . The magnetic surface finishing method according to  claim 5 , further comprising carrying out a burnishing process on the inner surface of the cylinder sleeve prior to arranging the magnetic pole inside the cylinder sleeve. 
     
     
         8 . The magnetic surface finishing method according to  claim 6 , wherein the magnetizable powder has a granulometry from 6 to 200 micrometers. 
     
     
         9 . The magnetic surface finishing method according to  claim 6 , wherein the magnetizable powder has a granulometry from 10 to 100 micrometers. 
     
     
         10 . The magnetic surface finishing method according to  claim 5 , wherein wearing down the plurality of peaks of the inner surface includes forming a surface finish on the inner surface having a rugosity with:
 a ratio between a peak density and a mean radius of curvature of peaks greater than 150 and less than 400; and   a ratio between the mean radius of curvature of peaks and an average height of peaks lower than 1500.   
     
     
         11 . The magnetic surface finishing method according to  claim 5 , wherein wearing down the plurality of peaks of the inner surface includes forming a peak density from 4,000 to 28,000 peaks per square millimeter. 
     
     
         12 . The magnetic surface finishing method according to  claim 5 , wherein wearing down the plurality of peaks of the inner surface includes forming a mean radius of curvature of peaks from 86 to 105 peaks per millimeter. 
     
     
         13 . The magnetic surface finishing method according to  claim 12 , wherein wearing down the plurality of peaks of the inner surface further includes forming a peak density from 4,000 to 28,000 peaks per square millimeter. 
     
     
         14 . The magnetic surface finishing method according to  claim 13 , wherein wearing down the plurality of peaks of the inner surface further includes forming a surface finish on the inner surface having a rugosity with:
 a ratio of the peak density to the mean radius of curvature of peaks between 150 and 400; and   a ratio of the mean radius of curvature of peaks to an average height of peaks lower than 1500.   
     
     
         15 . The cylinder sleeve according to  claim 1 , wherein the inner surface is a burnished, magnetic finished inner sliding surface. 
     
     
         16 . The cylinder sleeve according to  claim 15 , wherein the peak density is from 4,000 to 28,000 peaks per square millimeter. 
     
     
         17 . The cylinder sleeve according to  claim 15 , wherein the mean radius of curvature of peaks is from 86 to 105 peaks per millimeter. 
     
     
         18 . A cylinder sleeve for an internal combustion engine, comprising a bore-through cylindrical body having an inner sliding surface, wherein:
 the inner sliding surface has a surface finish and a rugosity;   the rugosity is defined by a valley-and-peak structure including a plurality of peaks and a plurality of valleys; and   the rugosity of the inner surface has:
 a ratio of a density of the plurality of peaks to a mean radius of curvature of the plurality of peaks between 150 and 400; and 
 a ratio of the mean radius of curvature to an average height of the plurality of peaks lower than 1500. 
   
     
     
         19 . The cylinder sleeve according to  claim 18 , wherein the inner surface is a burnished, magnetic finished inner sliding surface. 
     
     
         20 . The cylinder sleeve according to  claim 19 , wherein:
 the peak density is from 4,000 to 28,000 peaks per square millimeter; and   the mean radius of curvature of peaks is from 86 to 105 peaks per millimeter.